2. Development and structural characterization of nanodispersions - nanoformulation
The aim of this project is to develop new enzyme-immobilized systems and their use in adequate environments favoring the desired bioconversions. As new enzyme encapsulation systems we studied the organogels which are based on a matrix of a natural polymer around the enzymatic nanodispersion. The obtained system is a solid-like gel. The biocatalytic reactions can be carried out continuously offering simplified final product isolation and a possibility of enzyme reuse. The recent studies focused on the use of cellulose derivatives such as the hydroxypropylmethyl cellulose, HPMC as a gelling agent.
An alternative immobilization matrix consist on the use of mesoporous silica materials owing a hexagonal structure where the enzyme ca be entrapped.
We also develop new environments for mild biocatalytic reactions. This is the case of supercritical CO2 that can be applied to solubilized substrates with limited solubility in conventional solvents. The technique is considered as very suitable for bioconverting delicate products used in the foods and pharmaceuticals where the use of solvents are avoided.
Formation of microemulsion-based gels (MBG)
Lipase-immobilization in microemulsions-based organogels (MBG)
Relevant publications:
M. Zoumpanioti, H. Stamatis, A. Xenakis (2010) "Microemulsion-based organogels as matrices for lipase immobilization" Biotechnol.Advances, 28, 395-406F.
Michaux, M. Zoumpanioti, M. Papamentzelopoulou, M. J. Stebe., J. L. Blin, A. Xenakis (2010) "Immobilization and activity of Rhizomucor miehei lipase. Effect of the matrix properties prepared from nonionic fluorinated surfactants". Proc.Biochem. 45, 39-46
S. Avramiotis, V. Papadimitriou, E. Hatzara, V. Bekiari, P. Lianos, A. Xenakis (2007) "Lecithin Organogels Used as Bioactive Compounds Carriers. A Microdomain Properties Investigation" Langmuir, 23, 4438-4447
V. Papadimitriou, S. Pispas, S. Syriou, A.Pournara, M. Zoumpanioti, T. G. Sotiroudis, A.Xenakis (2008) "Biocompatible Microemulsions based on Limonene: Formulation, Structure and Applications" Lamgmuir, 24, 3380-3386.
C. Blattner, M. Zoumpanioti, J. Kroner, G. Schmeer, A. Xenakis, W. Kunz (2006) "Biocatalysis using lipase encapsulated in microemulsion-based organogels in supercritical carbon dioxide" J.Supercritical Fluids 36, 182-193.
